Light-emitting diodes (LEDs) intended for indication purposes have been used for a long time, but high-brightness LEDs, e.g. LEDs having a brightness that is high enough to enable general illumination of various locations such as rooms, have in a short period of time caused a significant growth in the LED and lighting applications market. High brightness LEDs are generally associated with a small size, a relatively high efficacy (and associated low temperature), a relatively long lifetime, a wide color gamut and ease of control. Naturally, such LEDs are of importance to lighting designers in developing new lighting applications. Such LEDs may also be utilized in replacing conventional light generation devices, such as filamented light bulbs or halogen lamps. Such LEDs are also generally capable of emitting light of various colors, which renders it possible to control the color of the light emitted from a luminaire comprising such LEDs.
In particular, light sources extending over a relatively large area, having variable color and homogeneous light distribution, may be provided by employing arrays comprising a plurality of red, green and blue LEDs covered by a light diffuser. This makes high-brightness LEDs attractive for all kinds of applications such as, for example, illumination or decoration of shop windows and public areas like exhibitions, theatres, airports etc. The ability of LEDs to provide very fast response times and the ability of LED-based RGB triplets to produce virtually any color makes LED-based RGB triples suitable for large-area lighting applications for visualizing moving color patterns or even video. Depending on LED density and/or controllability of the LEDs, such direct-view type lighting applications may range from single-color illumination panels to multi-color video displays.
While most conventional luminaries are intended to be permanently mounted at a certain location until the end of their lifespan, future LED lighting applications may have an increased emphasis on flexibility with regards to use and portability. Modular lighting is a step in this direction. Modular lighting refers to modules that can be assembled in order to obtain large lighting devices of various sizes and shapes. Notwithstanding the flexibility in adapting the size and shape of such modular lighting applications to the available space where the modular lighting application is to be installed, such modular lighting applications may be used to visualize moving light patterns (or video) on a screen that may have a size and a shape that in general deviates from standard rectangular liquid crystal display (LCD) devices. Substantially two-dimensional modules are sometimes referred to as tiles. Such a module may comprise various polygonal shapes, such as for example a square, triangle or pentagon shape. The modules are not limited to two-dimensional shapes but may have a three-dimensional shape, such as a cube or a pyramid. Portability may be improved by limiting the size of the individual modules. Fields of application for such modular lighting may for example be digital signage and atmosphere creation.
Conventionally, modules are usually mounted on a supporting frame and interconnected electrically by means of wiring and connectors. Other conventional systems make use of a wired lighting communication protocol, such as DMX512, to establish data communication with some external light pattern generator. Modules capable of wireless interconnection are also known.
In general, a modular lighting system is controlled by an external controller connected to at least one of the modules and serving as a light pattern generator for at least a portion of the lighting system. For driving the lighting system, the external controller in general needs to know about the exact geometric configuration of the lighting system beforehand (i.e. prior to or at power-up) and furthermore needs to have access to data paths interconnecting all modules, via which data paths the external controller may supply individual modules with temporally varying data (e.g. regarding luminance and color). However, the geometric shape and/or size of the modular lighting system is in general unknown to the external controller at power-up of the lighting system. Moreover, the geometric shape and/or size of the modular lighting system may change during operation of the lighting system, whereby already established data paths may be rendered defunct or inefficient (i.e. not optimal with regards to data path length from the external controller to a particular module).
Conventionally, optimal data paths are required to be programmed into the external controller prior to power-up of the lighting system by a skilled programmer. However, in this way slight modifications of the geometric shape and/or size of the lighting system during operation thereof, e.g. in response to a change of location of the lighting system, adaptation to user requirements, etc., requires an adaptation of the lighting software of the external controller. Thus, the presence of the skilled programmer during the entire period of operation of the lighting system is in general required.